This invention relates to solid preparations containing hydroxy mixed ethers and optionally other surfactants, polymers and inorganic or organic carriers, to a process for their production and to the use of the solid preparations as a starting compound for the production of laundry detergents, dishwashing detergents and cleaning compositions.
Today, machine-washed tableware has to meet stringent requirements. Thus, even tableware completely free from food residues is regarded as unsatisfactory when, after dishwashing, it still has whitish stains which are attributable to water hardness or other mineral salts and which come from water droplets that have remained on the tableware through lack of wetting agent and dried. Accordingly, to obtain bright, spotless tableware, rinse agents have to be used. The addition of liquid or solid rinse agent—which may be separately added or which is already present in ready-to-use form together with the detergent and/or regenerating salt (“2-in-1”, “3-in-1”, for example in the form of tablets and powders)—ensures that the water drains completely from the tableware so that the various surfaces are bright and free from residues at the end of the dishwashing program.
Commercially available rinse agents are mixtures of, for example, nonionic surfactants, solubilizers, organic acids and solvents, water and optionally preservative and perfumes. The function of the surfactants in these compositions is to influence the interfacial tension of the water in such a way that it is able to drain from the tableware as a thin, coherent film so that no droplets of water, streaks or films remain behind during the subsequent drying process (so-called wetting effect). Accordingly, another function of surfactants in rinse agents is to suppress the foam generated by food residues in the dishwashing machine. Since the rinse agents generally contain acids to improve the clear drying effect, the surfactants used also have to be relatively hydrolysis-resistant towards acids.
Rinse agents are used both in the home and in the institutional sector. In domestic dishwashers, the rinse agent is added after the prerinse and wash cycle at 40 to 65° C. Institutional dishwashers use only one wash liquor which is merely replenished by addition of the rinse agent solution from the preceding wash cycle. Accordingly, there is no complete replacement of water in the entire dishwashing program. Because of this, the rinse agent is also expected to have a foam-suppressing effect, to be temperature-stable in the event of a marked drop in temperature from 85 to 35° C. and, in addition, to be satisfactorily resistant to alkali metal and active chlorine compounds.
Reference is made in this connection to DE-A1 19738866 (Cognis) which describes surfactant mixtures containing nonionic surfactants of the hydroxy mixed ether and fatty alcohol polyglycol ether type which have very good foaming behavior and show excellent clear rinse effects in rinse agents.
The problem addressed by the present invention was to provide surfactants in solid form (solid preparations) for the production of solid laundry detergents, dishwashing detergents and cleaning compositions, more particularly solid dishwashing detergents, for example so-called “2-in-1” or “3-in-1” dishwashing detergents. The solid preparations would be distinguished by excellent “clear rinse” properties, by a foam-suppressing effect even in the presence of protein-containing soils, by stability even in the event of significant reductions in temperature, by dissolution without gelling and, in particular, by dissolving kinetics which would ensure that a high percentage of the nonionic surfactant was carried over into the rinse cycle of the machine program. In addition, it would be possible to produce solid cleaning formulations more easily. Also, the surfaces to be cleaned or rinsed would be finished in such a way that soil would be easier to remove in the next cleaning cycle.
The problem stated above has been solved by the provision of solid preparations which contain a combination of hydroxy mixed ethers and polymers in the mixing ratio according to the invention. Through the provision of these solid preparations, for example as a starting compound for laundry detergent, dishwashing detergent and cleaning formulations, the surfactant content and particularly the hydroxy mixed ether content can be reduced for the same high cleaning performance.
Nevertheless, very good wettability and a spotless shine of the surfaces to be cleaned are obtained in this way. The effect of adding polymers to rinse agents is that otherwise firmly adhering and often critical soils, for example starch-containing soils, can be completely removed in the next cleaning cycle. Such soils can be removed without additional manual treatment of the tableware.